Apparatus for and method of removing distortions from printing plates



May 29, 1934. R, Ml DUGDALE 1,960,840

APPARATUS FOR AND METHOD OF REMOVING DISTORTIONS FROM PRINTING PLATES Filed July 1?-, 1931 Y 3,9@ A. A 2413 jfl-9" Patented May 29, 1934 Unire starts PT FFECE 1,960,840 AFPARTUS FOR AND METHOD OF REMOV- NG DSTORTIONS PLATE S FROM PRINTING Application July 17, 1931, Serial No. 551,433

3 Claims.

This invention relates to a method oi and apparatus for straightening and reinforcing printing plates such, for example, as the type shown in my United States Patent No. 1,801,593, granted April 21, 1931, which plates are used in conjunction with printing devices of the type shown in my United States Patent No. 1,801,592, granted April 21, 1931.

These plates, provided with embossed characters, are usually made or soit, thin metal and as they are usually carried on the person often become bent or distorted. The slightest distortion interferes with the printing operation and results either in non-uniform printing or an incomplete reproduction oi the characters. Consequently damaged plates have to be discarded and new ones substituted.

Among the objects of my invention are to pros vide a simple and eiiicient method and apparatus adapted to straighten and remove distortions from such printing plates without injuring the embossed characters thereon, and preferably also to impart to the face of the plate a convex curvature which provides a reinforcement and compensates for the tendency of the central portion of the plate to sag or yield during the printing operation.

One embodiment of my invention, chosen for the purpose of illustration, is shown in the accompanying drawing, wherein:

Fig. 1 is a side elevation oi the apparatus;

Fig. 2 is a section on the line 2-2 of Fig. 1 with the printing plate removed;

Fig. 3 is a section on the line 3-3 of Fig. 2;

Fig. 4 is a bottom View of one form of printing plate;

Fig. 5 is an enlarged section taken on the line 5-5 of Fig. 4; and

Fig. 6 is a section taken on the line 6 6 of Fig. 4.

The printing plate 1 usually employed in conjunction with printing devices of the aforesaid type preferably is stamped from sheet metal and shaped to provide a raised flat central portion or -top 2 and marginal flanges 3 spaced below the top by integral shoulders bordering a bottom recess 4, the opposite longitudinal flanges having inturned wings 5. The plate, as shown in Fig. L1, is preferably rectangular in form, although other Vshapes may be selected according to the construction of the printing device in which a plate is to be inserted. Embossed characters 6 are stamped on the top 2 to furnish the name and address of a customer or such other data as may be desirable, and when the plate is to be used in a printing device of the aforesaid type, the characters may be arranged in non-reversed order. A thin sheet of cardboard '7 iits within the recess 4 and is retained therein by means of the inturned wings 5 and a tongue 8 struck from one of the flanges 3. A more complete description of this type plate is set forth in my United States Patent No. 1,801,593, granted April 21, 1931.

The illustrated machine includes a frame 10 having an overhanging portion 11 in which a plunger or stem 12 is slidably mounted. A handle or lever 13 is pivotally secured to the overhanging portion 11 and is provided with a cam 14 which engages a plate 15 secured to the upper end oi the plunger 12. A spring 16 mounted in recess 17 engages the under side of plate 15 and normally holds the plunger in retracted position, as shown in Fig. 1.

The lower end of the plunger is provided with a pressure head 18 having a convex surface, as shown in Figs. 2 and 3. A die 19 secured to the frame by a machine screw 19' preferably comprises a bed portion having a plurality of spaced longitudinally extending arcuate ribs 20 and longitudinally extending curved shoulders 21 which together define a concave surface of slightly less curvature than that of the head 16. The sides of the die are provided with anges 22 which are inturned at one end, as indicated at 22a, to hold the printing plate in fixed position and to prevent longitudinal movement away from the open end.

The printing plate to be straightened and/or reinforced is inserted in the die, face downward, so that the ribs 20 engage the face of the plate between the rows of embossed characters and the shoulders 21 engage the marginal portions of its face, as shown in Fig. l. When thus positioned the handle 13 is swung downwardly into the position shown by the dot and dash lines of Fig. 1, thereby squeezing and clamping the plate between the die and the head, the latter engaging the back of the plate intermediate its marginal iianges 3 and inturned wings 5.

It will be noted that due to the cam action the pressure is progressively applied to the plate and is maintained forV the requisite time, in contradistinction to an instantaneous application such as would result from a sudden impact. This is particularly advantageous in that the ribbed portion of the die does not score or otherwise injure the face oi the plate.

The plate emerges from the apparatus free from distortions and with a convex curvature both longitudinally and transversely, as shown in Figs. 5 and 6. In the curved conguration thus imparted to the plate its material is disposed in position better to withstand distortion both in use and in handling than is a similar flat plate; such reinforcement of the plate is obtained without adding material thereto. The convex curvature is particularly desirable in that it resists the usual tendency of the central portion of a plate to sag or yield during the printing operation, thus ensuring a clear reproduction of the characters in the center of the plate as well as those around the margin.

It will of course be understood that the utility of this apparatus is not confined to straightening and reinforcing damaged or distorted printing plates, but it may also be used to provide a convex curvature to new plates after the embossing operation, thereby reinforcing the same and ensuring a clear and uniform reproduction of its printing characters.

While I have shown and described one desirable embodiment of my invention, I wish it understood that various changes in shape, proportion and arrangement of parts as well as the substitution of equivalent elements for those herein shown and described may be made without departing from the spirit and scope of the invention as set forth in the appended claims.

I claim:

1. Apparatus for removing distortions from and imparting a reinforcing curvature to a printing plate of the class described having embossed characters thereon, comprising a die adapted to receive and hold in fixed position the printing plate, said die having a concave surface provided with a plurality of recesses arranged to receive the embossed characters on said plate while affording points of contact with the face of said plate intermediate some of its characters, a plunger having a head provided With a convex curvature and engageable With the opposite face of said plate, and means for actuating said plunger to clamp said plate between the die and head.

2. Apparatus for removing distortions from and imparting a reinforcing curvature to a printing plate of the class described having rows of embossed characters, comprising a die having a plurality of longitudinally extending curved ribs dening a longitudinally and transversely concave contacting surface, said die being adapted to receive and hold the printing plate with said ribs engaging the face of said plate between the rows of characters, a plunger having a head provided with a convex surface engageable with the opposite face of said plate, and means for actuating said plunger to clamp said plate between the die and head.

3. The method of removing distortions from and providing a reinforcement to a printing plate of the class described having embossed characters thereon, which comprises squeezing the printing plate between opposed pressure members at points intermediate its embossed characters, and simultaneously imparting to the embossed surface of said plate a convex curvature suicient to compensate for the tendency of its central portion to sag when subjected to the printing operation.

RICHARD M. DUGDALE. 

